While not limited thereto, the present invention is particularly adapted for use in an endothermic chemical reaction such as that employed to produce water-gas. In a reaction of this type, water vapor is reacted with a methane-rich gas such as natural gas, the methane-rich gas being transformed into a synthesized gas usually consisting of hydrogen and carbon dioxide and/or carbon monoxide. A dissociation process of this type is preferably carried out in a closed processing chamber filled with a catalyst, usually nickel, the chamber being heated by means of hot gases which flow around the chamber, or through tubes within the chamber, in which the dissociation process occurs.
It is known, for example, that helium emanating from a nuclear reactor can be used for the purpose of heating the reaction chamber in such an endothermic process. In the past, such a cooling medium from a nuclear reactor has been used to heat a dissociation reaction furnace of this type by passing the nuclear reactor cooling gas through conduits or flow chambers within the reaction chamber itself.
In view of the fact that catalyst-filled reaction chambers for carrying out endothermic reactions can have only a relatively small diameter in view of the limited thermal conductivity of gases passing therethrough and the requirement for uniform heating of such gases, it becomes necessary to employ a very large number of dissociation tubes within each reaction chamber in order to have an economical installation. Since it is necessary to provide for appreciable thermal expansion when heating the dissociation tubes with a nuclear reactor cooling medium, consideration of this expansion plays a significant role in the design of such reaction chambers. Consideration must be taken of the fact that the heat exchanger is disposed within a conduit to which high pressure nuclear reactor cooling gases are subject. In addition, the stresses on the tubing connecting the heat exchanger to the reaction chamber, particularly at the seam welds and in the vicinity of the bushings around the conduits connecting the heat exchanger to the reaction chamber, are very critical. Furthermore, in the past, only a single reaction chamber was contemplated, the chamber being heated by the cooling gas from a nuclear reactor flowing through tubing within the reactor.